Unsaturated lactones and lactams occur widely in nature and possess extensive physiological activity. Our recent work on the carbonylation of vinylmercurials derived from propargylic alcohols provides a novel new route to Delta, alpha, beta-butenolides. We are presently studying the direct palladium promoted carbonylation of these same propargylic alcohols as a more convenient and general route to butenolides. The palladium promoted carbonylation of acetylenic phenols is being examined as a new route to coumarins and coumestans. The mercuration of propargylic amines is being studied. The resulting vinylmercurials appear to be useful precursors to alpha-methylene-beta-lactams via carbonylation. Work is also progressing on the thallation-carbonylation of benzyl and phenethyl alcohols as a convenient route to phthalides and 3,4-dihydroisocoumarins. These new synthetic procedures offer real advantages over present synthetic routes to these physiologically active ring systems and should provide a number of new unsaturated lactones and lactams possessing interesting biological activity.